feat(mission-control): swap tiles by dragging their header

src/ClaudeDo.Ui/ViewModels/MissionControlViewModel.cs

@@ -729,7 +729,18 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
         pane.Dispose();
     }
 
-    // Mirrors ConPtySessions' add/remove 1:1 into Panes (typed as the pane abstraction).
+    /// <summary>Swaps two tiles' slots (overview-grid drag and drop); also reorders the focus-mode tabs.</summary>
+    public void SwapPanes(ConPtyPaneViewModel a, ConPtyPaneViewModel b)
+    {
+        var i = ConPtySessions.IndexOf(a);
+        var j = ConPtySessions.IndexOf(b);
+        if (i < 0 || j < 0 || i == j) return;
+        if (i > j) (i, j) = (j, i);
+        ConPtySessions.Move(i, j);
+        ConPtySessions.Move(j - 1, i);
+    }
+
+    // Mirrors ConPtySessions' add/remove/move 1:1 into Panes (typed as the pane abstraction).
     private void OnConPtySessionsChanged(object? sender, NotifyCollectionChangedEventArgs e)
     {
         switch (e.Action)
@@ -740,6 +751,9 @@ public sealed partial class MissionControlViewModel : ViewModelBase, IDisposable
             case NotifyCollectionChangedAction.Remove:
                 Panes.RemoveAt(e.OldStartingIndex);
                 break;
+            case NotifyCollectionChangedAction.Move:
+                Panes.Move(e.OldStartingIndex, e.NewStartingIndex);
+                break;
             default: // Reset
                 Panes.Clear();
                 break;

src/ClaudeDo.Ui/Views/MissionControl/ConPtyPaneView.axaml

@@ -14,8 +14,8 @@
       <Border DockPanel.Dock="Left" Width="3"
               Background="{Binding IdentityColorKey, Converter={x:Static cconv:DotBrushConverter.Instance}}" />
 
-      <!-- Header: title + close -->
+      <!-- Header: title + close; also the drag handle for reordering tiles (MissionControlView) -->
-      <Border DockPanel.Dock="Top"
+      <Border DockPanel.Dock="Top" Classes="pane-header" Cursor="SizeAll"
               Background="{DynamicResource Surface2Brush}"
               BorderBrush="{DynamicResource LineBrush}"
               BorderThickness="0,0,0,1" Padding="8,3">

src/ClaudeDo.Ui/Views/MissionControl/MissionControlView.axaml

@@ -16,6 +16,16 @@
       <mc:ConPtyPaneHost Margin="6" />
     </DataTemplate>
   </UserControl.DataTemplates>
+  <UserControl.Styles>
+    <!-- Drop target outline while dragging a tile by its header; matches the pane's Margin/CornerRadius. -->
+    <Style Selector="Border.pane-drop-hint">
+      <Setter Property="Margin" Value="6" />
+      <Setter Property="CornerRadius" Value="10" />
+      <Setter Property="BorderThickness" Value="2" />
+      <Setter Property="BorderBrush" Value="{DynamicResource AccentBrush}" />
+      <Setter Property="IsHitTestVisible" Value="False" />
+    </Style>
+  </UserControl.Styles>
   <DockPanel LastChildFill="True" Background="{DynamicResource VoidBrush}">
 
     <!-- Header -->

src/ClaudeDo.Ui/Views/MissionControl/MissionControlView.axaml.cs

@@ -4,12 +4,14 @@ using System.ComponentModel;
 using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
+using Avalonia.Input;
 using Avalonia.Layout;
 using Avalonia.Media;
 using Avalonia.Platform.Storage;
 using Avalonia.VisualTree;
 using ClaudeDo.Ui.Localization;
 using ClaudeDo.Ui.ViewModels;
+using ClaudeDo.Ui.ViewModels.MissionControl;
 
 namespace ClaudeDo.Ui.Views.MissionControl;
 
@@ -33,6 +35,70 @@ public partial class MissionControlView : UserControl
         // Button runs its Command, and a synchronous Hide unbinds that Command first.
         RecentSessionsList.AddHandler(Button.ClickEvent,
             (_, _) => Avalonia.Threading.Dispatcher.UIThread.Post(() => RecentSessionsButton.Flyout?.Hide()));
+        OverviewGrid.AddHandler(PointerPressedEvent, OnTilePointerPressed);
+        OverviewGrid.AddHandler(PointerMovedEvent, OnTilePointerMoved);
+        OverviewGrid.AddHandler(PointerReleasedEvent, OnTilePointerReleased);
+    }
+
+    private const double DragThreshold = 4;
+
+    /// <summary>Tile presenter whose header was pressed; null when no tile drag is pending.</summary>
+    private ContentControl? _dragSource;
+    private Point _dragStart;
+    private bool _dragging;
+    private Border? _dropHint;
+
+    // Buttons in the header mark PointerPressed handled, so only the bare header starts a drag.
+    private void OnTilePointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (!e.GetCurrentPoint(OverviewGrid).Properties.IsLeftButtonPressed || e.Source is not Visual source) return;
+        var chain = source.GetSelfAndVisualAncestors().ToList();
+        if (!chain.OfType<Border>().Any(b => b.Classes.Contains("pane-header"))) return;
+        _dragSource = chain.OfType<ContentControl>().FirstOrDefault(c => ReferenceEquals(c.Parent, OverviewGrid));
+        _dragStart = e.GetPosition(OverviewGrid);
+    }
+
+    private void OnTilePointerMoved(object? sender, PointerEventArgs e)
+    {
+        if (_dragSource is null) return;
+        if (!e.GetCurrentPoint(OverviewGrid).Properties.IsLeftButtonPressed) { EndTileDrag(); return; }
+
+        var pos = e.GetPosition(OverviewGrid);
+        if (!_dragging)
+        {
+            if (Math.Abs(pos.X - _dragStart.X) < DragThreshold && Math.Abs(pos.Y - _dragStart.Y) < DragThreshold) return;
+            _dragging = true;
+            _dragSource.Opacity = 0.5;
+            _dropHint = new Border { Classes = { "pane-drop-hint" }, IsVisible = false };
+            OverviewGrid.Children.Add(_dropHint);
+        }
+
+        var target = TileAt(pos);
+        _dropHint!.IsVisible = target is not null;
+        if (target is null) return;
+        Grid.SetColumn(_dropHint, Grid.GetColumn(target));
+        Grid.SetRow(_dropHint, Grid.GetRow(target));
+    }
+
+    private void OnTilePointerReleased(object? sender, PointerReleasedEventArgs e)
+    {
+        var source = _dragSource;
+        var target = _dragging ? TileAt(e.GetPosition(OverviewGrid)) : null;
+        EndTileDrag();
+        if (source?.Content is ConPtyPaneViewModel a && target?.Content is ConPtyPaneViewModel b)
+            _vm?.SwapPanes(a, b);
+    }
+
+    private ContentControl? TileAt(Point pos) => OverviewGrid.Children.OfType<ContentControl>()
+        .FirstOrDefault(c => !ReferenceEquals(c, _dragSource) && c.Bounds.Contains(pos));
+
+    private void EndTileDrag()
+    {
+        if (_dragSource is not null) _dragSource.Opacity = 1;
+        if (_dropHint is not null) OverviewGrid.Children.Remove(_dropHint);
+        _dragSource = null;
+        _dropHint = null;
+        _dragging = false;
     }
 
     private void OnSessionFlyoutOpening(object? sender, EventArgs e) => _ = _vm?.RefreshSessionTargetsAsync();

tests/ClaudeDo.Ui.Tests/ViewModels/MissionControlViewModelTests.cs

@@ -491,6 +491,22 @@ public class MissionControlViewModelTests : IDisposable
         Assert.Equal(2, vm.ColumnCount);
     }
 
+    [Fact]
+    public async Task SwapPanes_SwapsSlots_InBothCollections()
+    {
+        var worker = new FakeWorker();
+        using var vm = BuildVm(worker);
+        await vm.OpenConPtySessionAsync("t1");
+        await vm.OpenConPtySessionAsync("t2");
+        await vm.OpenConPtySessionAsync("t3");
+        var (a, b, c) = (vm.Panes[0], vm.Panes[1], vm.Panes[2]);
+
+        vm.SwapPanes(c, a);
+
+        Assert.Equal(new[] { c, b, a }, vm.Panes);
+        Assert.Equal(new[] { c, b, a }, vm.ConPtySessions);
+    }
+
     [Fact]
     public async Task SetColumns_OverridesAutoCapsAtPaneCountAndPersists()
     {